System for relocating catheter-supported electrodes on segmented model

ABSTRACT

Guidance to an operator to more accurately position electrodes upon a segmented heart model (SGM). The SGM is included in a map panel on a display screen. A catheter advanced into a beating heart supports one or more electrodes. During a single beat of the heart, an image is obtained with darkened portions corresponding to locations of the electrodes. The image is presented in the same map panel as the SGM. The current location of the electrodes is confirmed relative to the SGM, either manually or through automated software algorithms. EP data is captured that represents electrophysiological signals of the beating heart at the current location for each of the electrodes. A signal processing algorithm is applied to the captured EP data in view of the confirmed current location of the electrodes to result in a calculation that is mapped at the confirmed location of the electrodes.

This application claims the benefit of priority under 35 U.S.C. Section120 of U.S. application Ser. No. 12/117,654, now U.S. Pat. No.8,224,432, filed May 8, 2008, entitled Rapid 3D Mapping UsingMultielectrode Position Data and under 35 U.S.C. Section 119(e) of U.S.Provisional Application Ser. No. 60/916,749, filed May 8, 2007, each ofwhich is hereby incorporated by reference in their respectiveentireties.

FIELD OF THE INVENTION

This invention is directed to improvements in electrophysiology (EP)systems and procedures including software that assists in datamanagement across various systems in the EP laboratory including systemsthat provide electrogram capture, electrogram analysis, fluoroscopicdisplay, and that permit, among other things, 3D colorized mapping ofcaptured and analyzed data to provide an electrophysiologist withinformation in a form that assists in his or her diagnosis ordocumenting that an EP issue has been resolved.

BACKGROUND OF THE INVENTION

Many cardiac arrhythmias are caused by conduction defects that interferewith the propagation of normal electrical signals within the heart. Themethod adopted to treat arrhythmia is dependent on the nature andposition of the underling conduction defect. Thus, electrophysiologicalmapping plays an important role in measuring the electrical activity ofthe heart. These techniques often require specialized equipment tolocate the position of catheters in physical space and reconstructingthe shape of the chamber from multiple site recordings. It would bedesirable to provide 3D mapping without such equipment.

State of the Art 3D mapping systems use magnetic fields, electricalfields or ultrasound to localize catheters. The main disadvantage ofthese systems is the prohibitive cost involved with the equipment andthe need for both a conventional EP recording system and a separate 3Dmapping/localization system. While manual positioning is not as accurateas current technologies, it is significantly more cost effective thanconventional EP mapping systems and can be performed more rapidly.

It remains necessary to locate a target (active) site if an arrhythmiais to be terminated. A number of catheter locating systems are known inthe art, but each introduces components and complexity to EP procedures.EP operators, however, are usually quite capable of piloting an EPcatheter to a desired site within a patient's vasculature, particularlywith fluoroscopic assistance. A difficulty remains, even if the locationof the catheter is estimated based on fluorscopic guidance, in matchingindwelling EP electrodes to sites on a cardiac model. This problem isall the more difficult when the model is rendered in 3D.

In part, the operator has data captured by a variety of systems. Forexample, electrogram channels monitor signals from indwellingelectrodes, such as intracardiac electrodes and reference electrodes,and that information has to be coordinated with an anatomical (e.g.,cardiac) model. Fluoroscopic images of the anatomy generally have noconnection to other systems in the EP lab, and so piloting a catheterthat lacks a locating system is done as a parallel, distinct part of theEP procedure. Cardiac mapping, therefore, has required great effort at atime when the operator's attention needs to focus on the patient or inlabs where cost is an impediment and a highly trained technician is notavailable to operate a complex 3D mapping system.

The present invention addresses one or more of these problems.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, anelectrophysiology (EP) system for use by an operator is provided. Thesystem includes an interface having an output device comprising adisplay and an input device comprising a control panel, a processor, andcode executing in the processor. The code comprises at least a firstroutine that is operative to respond to user-interaction through thecontrol panel. Among other functionality, the code provides a selectionof channels having associated EP data that is viewable on the display,informs a map module of any selections made among the selection ofchannels so as to link any EP data associated with any selections to themap module, permits positioning of the channels at respective locationson a template model to define a set-up, and saves the set-up for use inone or more procedures. The code is further operative to calculatevalues as a function of both the EP data and any positioning of thechannels to said respective locations.

In further, optional arrangements of the system described above, thecode can be arranged to: permit positioning of the channels through adragging operation performed through the interface; display the EP dataassociated with any selections of channels at any of said respectivelocations on the template model in accordance with a color scale usinginterpolation calculations; permit user-positioning of a boundary zonealong a portion of a surface of the template model which can be used toexclude the portion of the surface of the template model from anyinterpolation calculations; permit a region of the surface of thetemplate model to be selected and transformed into a transparent region;to capture images (e.g., a fluoroscopic image) as part of a record of adata capture event; and to exchange messages that permit synchronizationof displays of electrocardiogram waveforms and other EP equipment.

In accordance with a further aspect of the present invention, anelectrophysiology system useful for conducting an EP data captureprocedure is provided. This system comprises a computer having a memory,a processor, and computer code executing in the processor and operablethrough a user-interface. A display is communicatively coupled to thecomputer. A template model of a surface of a heart is stored in thememory and selectable via the user-interface for display on the display.At least one set-up is establishable using the user-interface, theset-up comprising a plurality of particular locations on the surface ofthe template model at which a corresponding plurality of ECG channelsare associable. A connection to an EP system receives the EP data fromthe plurality of the ECG channels. The computer code in this system isoperative to impart a color coding across the surface of the templatemodel as a function of the set-up and as a further function of any EPdata received through the connection.

In further, optional arrangements of the system described in theparagraph immediately above, color coding comprises a spectrum of colorson a color scale in which a color is assigned to each particularlocation and wherein the computer code imparts colors from the colorscale across the surface of the template model by interpolation. Also, auser-positionable boundary zone can be stored in the memory as part ofthe template model, with the boundary zone being used by the computercode to exclude a portion of the surface of the template model from theinterpolation of colors. Optionally, the particular locations on thesurface of the template model that comprise the set-up arerepositionable.

In accordance with yet a further aspect of the present invention, anelectrophysiology system is provided which has an interface comprisingan output device comprising a display and an input device comprising acontrol panel. A processor has code executing therein that comprises atleast a first routine operative to respond to user-interaction throughthe interface to reposition one or more markers presented on the displayand to automatically compute EP data values as a function of therepositioning of the one or more markers. The interface provided inaccordance with this particular aspect of the invention optionallyprovides a map having a surface depicting the EP data values thereupon.When a map is provided, the code can respond to the user-interaction byproviding updates to the map. An event log can be provided through theinterface as well, and the code can respond to certain user-interactionswith updates being made to the event log.

In yet another aspect of the present invention, a computer-assistedmethod for guiding an operator in a placement of indwelling electrodesis disclosed. In the disclosed method, a template model of a heart isprovided on a display connected to the computer. A “set-up” is includedwithin the display of the template model of the heart in which aplurality of locations are marked on the template model as locationsthat correspond to a respective plurality of ECG channels. A catheterhaving a proximal end and a distal end that supports multiple electrodesis advanced into the heart of a patient, and the multiple electrodes arepiloted (e.g., navigated) into an orientation that generally coincideswith the set-up on the template model surface by manipulating theproximal end of the catheter. PP data is captured at the pilotedlocations onto electrogram channels associated with the respective onesof the multiple electrodes. In this way, the catheter is navigated freeof a precision navigation device.

In further, optional aspects of the foregoing method, a set of datapoints is stored wherein each data point has a location that correspondsto a respective location of one of the points in the set-up and a valuethat corresponds to the EP data on that channel. Also, the set-upincluded in the display of the template model can be pre-defined orconstructed by the user using controls provided on the EP systeminterface. Furthermore, as EP data is captured, portions of the templatemodel can be caused to have an opacity that is greater than portions ofthe template model in which there has been less or no mapping of EPdata.

In still further aspects of the invention, a computer-assisted methodfor guiding an operator in defining electrode positions upon a displayof a segmented heart model is provided in order to construct a moreaccurate map than achievable without such guidance. The segmented heartmodel is included in a map panel on a display screen. The methodcomprises the steps of: advancing a catheter into a beating heart, thecatheter having a proximal end and a distal end that supports one ormore electrodes; obtaining an image during a beat of the heart, theimage including one or more darkened portions corresponding to locationsof the one or more electrodes; presenting the image in the same mappanel that includes the display of the segmented heart model; confirminga current location of the one or more electrodes at the actual positionof the catheter relative to the segmented heart model; capturing EP datathat represents electrophysiological signals of the beating heart at thecurrent location for each of the one or more electrodes; applying asignal processing algorithm to the captured EP data in view of theconfirmed current location of the one or more electrodes to result in acalculation; and mapping the calculation at the confirmed location ofthe one or more electrodes.

A system in accordance with the foregoing method comprises means forobtaining an image during a beat of a heart, the image including one ormore darkened portions corresponding to locations of one or moreindwelling electrodes supported on a catheter; first software codeexecuting so as to present the image in the same map panel that includesthe display of the segmented heart model; second software code executingso as to confirm a current location of the one or more electrodes at theactual position of the catheter relative to the segmented model; meansfor capturing EP data that represents electrophysiological signals ofthe beating heart at the current location for each of the one or moreelectrodes; third software code executing so as to apply a signalprocessing algorithm to the captured EP data in view of the confirmedcurrent location of the one or more electrodes to result in acalculation; and fourth software code executing so as to map thecalculation at the confirmed location of the one or more electrodes.

These and other aspects, features, and steps can be better appreciatedfrom the following discussion of certain embodiments and theaccompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram concerning user interaction through asoftware-based user interface with a map module;

FIG. 2 illustrates an embodiment of certain panels that can be providedby the user interface for setting up a 3D map configuration;

FIG. 3 illustrates an embodiment of certain panels that can be providedby the user interface for mapping EP data that has been acquiredsequentially onto a 3D anatomical model and for managing such data;

FIG. 4 illustrates an embodiment of a user interface associated with anEP system for capturing and presenting electrograms for multiplechannels, which further includes interactive graphical markers that arepositionable and repositionable by a user through the user interface;

FIG. 5 illustrates an optional feature in which the opacity of the 3Dmap increases at locations that include mapped EP data;

FIG. 6 illustrates the panels of FIG. 3, and now shows an optionalmapping of EP data that has been acquired from a multi-pole electrodeonto a 3D anatomical model and an interface for managing such data;

FIG. 7 is a flow diagram illustrating an event log review mode inaccordance with a further aspect of the invention; and

FIGS. 8A and 8B illustrate exemplary 3D maps that are displayable intandem to assist a clinician in comparing the behavior of pre- andpost-operative cardiac tissue.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

By way of overview and introduction, the present invention concerns 3-Dmapping of cardiac data obtained during the course of anelectrophysiology procedure. A segmented model of a heart can beacquired from a CT scan of a patient, or from a library of “typical”anatomies for patients having like characteristics. A software-basedsystem populates the segmented model with data points that define a 3Dmap. The EP data at each data point is extracted from electrogramscaptured for one or more channels. The EP data for each channel isassociated with an electrode and the location of that electrode andhence the data point on the model can be defined on the map in severalways that simplify the equipment and operative steps that are requiredto construct a meaningful map, as described below.

In particular, and still by way of overview, the locations of one ormore channels can be defined on a template model of a heart and storedfor recall and use in a number of procedures. A “set-up” is a positionof a single-pole or multipole catheter at which data is to be collectedfor a given procedure (VT mapping, typical right atrial flutter, etc.).A defined set-up is particularly desirable when using a multi-electrodecatheter such as a twenty pole catheter because the operator can pilotthe catheter into the orientation indicated on the template and thencapture EP data without being concerned with the precise location of anyof the particular electrodes. In this regard, it can be appreciated thata set-up can be pre-defined by the software or user defined. In eithercase, the set-up can be selected through controls on the EP system(e.g., the Lab System Pro 2.4 available from C. R. Bard, Inc. of MurrayHill, N.J.) which causes pre-positioned points to display within thesegmented model. These pre-positioned points can become data points oncethe operator confirms, e.g., with fluoroscopic assistance, that thecatheter has been guided into a position that approximates the catheterset-up. Once the desired position and orientation has been confirmed bythe operator, using his professional skill and judgment, the data can becaptured (recorded) by transferring the electrogram information fromeach channel to the particular point in the set-up that is associatedwith that electrogram data.

Referring now to FIG. 1 a software module that operates in conjunctionwith an electrophysiology (“EP”) laboratory system, such as theaforementioned Lab System Pro (“LS Pro”), provides functionality thatenables the user to rapidly apply three cardiac data points capturedduring an EP procedure onto a 3-D anatomical model of the heart.

At block 102, an optional test is performed to ensure that the operatoris using an authorized catheter or otherwise has valid access to the mapmodule functionality. At block 102, a test is made to determine whetheran access key entered through the interface is valid. Until a valid keyis entered into the module, the operator is not granted access to themap module's functionality. As can be understood, a module can beimplemented without the access key test.

Once the map module has been activated, a basic usage scenario includes“setup” followed by the repeated steps of positioning the electrogram,determining a mapping channel location on the anatomy in the 3D View,and capturing data points. Generally, setup includes opening orestablishing a patient record for a session.

At block 104, the software is configured in order to be able to rendercardiac data onto a three dimensional surface. The configuration stepsinclude steps taken through the map module itself, as well as stepstaken on the EP system. Referring briefly to FIG. 2, a channel setuppage 200 of the map module is shown in exemplary form. This page isaccessed by selecting an appropriate tab such as tab 202 or using anyother control that can be provided for such selection through the userinterface. The channel setup page enables the user to define whichchannel is for mapping, which channel is to be the reference channel andwhich ECG channel is to be displayed in conjunction with the othertraces. These selections are made in region 204 of the channel setuppage, preferably with prompts provided by a pull-down selection listshowing the active channels that are available for selection. Preferablythe EP system informs the map module of the active channels throughconventional messaging. The active channels should correspond to theelectrodes that have been affixed or inserted within the anatomy of apatient or that were active during the EP procedure whose electrogramsare being provided to the map module (that is, when the map module isbeing used after the EP procedure). Region 206 shows the set ofavailable channels in an exemplary setup. Among the available channels,six have been designated on a segmented model of the heart, as shown inpanel 208. In particular, the six channels which have been designated onthe heart are the three HBE channels, the HRA channel, and the two CSchannels. The remaining channels can be selected by dragging thechannels from the left panel 206 to a location on the heart image withinthe anatomy panel 208 that generally corresponds to its location in thepatient. In other words, the user interface permits interaction with theheart template and a selection of channels such that the channels can bepositioned and repositioned using a mouse or similar input device.

Each of the channels available for selection has an associatedelectrogram that is viewable on the EP system. Even if a channel isavailable for selection, an operator may elect to deselect or not selecta given channel from the template based on clinical conditions. Forexample, if an undesirably noisy signal is being read on a particularchannel, then that channel might be deselected or not selected, andanother channel dragged to the template for use in a current procedureor in a review mode, as discussed below. If the voltage on one of thechannels is low, the user interface of the map module allows editing ofthe anatomy so as to exclude certain tissue from the mathematicalmodels. For example, the operator can paint that location of low voltagereading as a “scar” and thereby preclude any further measurements atthat electrode position. The scar is added to the model by aclick-and-drag operation in which tissue on the model at the locationsof the input device are assigned a color outside of the color scale thatindicates local activation or any other parameter of interest, such asgrey, black or brown.

Also, the initially selected channels appear as grey or uncoloredmarkers (e.g., spheres) on the segmented model because those positionsare not associated with any EP data as of yet. Once the physiciannavigates the catheter to those positions within the heart, then themodel can be updated by recording the EP data and associating that datawith the designated positions on the model.

In FIG. 2, a particular CT cardiac image has been selected, and thisimage can be an image of the patient or an image taken from a library ofcardiac CT images. The CT image shown in panel 208 comprises a segmentedmodel of a heart as understood by those of skill in the art, whichprovides a hollow surface that approximates the internal surface of anactual heart. Once a desired set of channels has been positioned on aparticular heart, it can be saved as a template or setup for use in apresent procedure, or in a future procedure. For example, a template canbe saved under the title “right isthmus dependent flutter setup,” andthat template can be used for more than one patient who generally fitsthe criteria for the particular segmented model that has been selected(e.g., a model of a normal heart of a 160 lb Male) and saved in thattemplate. As well, multiple templates can be called up and combined, forexample, to map multiple portions or chambers of the heart.

In addition, and as discussed with regard to FIGS. 8A and 8B below, thesaved templates can be saved again after data has been acquired. As oneexample, a particular template can be saved as a pre-ablation and apost-ablation map with the electrodes at particular positions in bothmaps.

In the event that the user wishes to locate a channel elsewhere on theheart, the user can drag the original location of the channel to a newlocation, by interacting with the channel markers displayed within thepane 208.

The setup (block 104) also requires that a region of interest bespecified, generally, a region that spans one beat. (In this respect,the region of interest can be, but is not limited to being, synonymouswith a beat of interest.) Also, a reference marker must be establishedat a particular location on the electrogram waveform of the selectedreference channel. Both of these settings can be done through a EPsystem such as the LS Pro. Turn briefly to FIG. 4, a region of interestacross one beat of the heart can be identified by clicking and/ordragging region of interest end point markers 402, 404 as shown in FIG.4. The region of interest markers 402, 404 are graphical objects thatcan be manipulated and have their values updated by dragging and thenreleasing them within an active window. This might be necessary, forexample, if the cardiac rhythm changes during the course of an EPprocedure, and can be done without specifying any particular number ofmilliseconds before or after a beat as required in prior-art trial anderror systems. The user can review the beat across all of the channelson the EP system and move the markers through interaction with the GUI.The reference marker 406 is identified by clicking on a desired point ofa reference channel such as the point of highest peak, point of steepestdownslope, etc., also through interaction with the GUI. Alternatively,the software executing in the EP system can operate to identify andautomatically position (subject to user confirmation or change) thereference channel marker at a location between the region of interestmarkers 402, 404 so as to coincide with a prescribed signal pattern ofinterest, including a highest/lowest peak, point of steepest downslope,and any other parameter that can be prescribed. The EP System does thisusing a conventional algorithm. Thus, in the case of peak detection, apeak within the region of interest is located based on a configurationvalue that can be preset or reassigned a value in a setup screen of thesystem. Of course, the prescribed signal pattern can be selected by theoperator, with the result being that the operator can have the EP systemautomatically locate that signal feature between the region of interestmarkers rather than doing so manually.

By defining a region of interest about a particular heart beat, and bydesignating a mapping channel and a reference channel,electrophysiologic data can be captured and associated with each channelof the catheter and, likewise, associated with the selected positions onthe selected anatomical model. The map module can be utilized inreal-time throughout the course of an EP procedure, that is, to showsingle-beat updates to the EP data, map and calculations, orretrospectively in a review mode.

Referring now to Block 106 a user selects the map mode such as byinteracting with tab or control 210 which calls up a map display 300.The map display includes controls suitable for generating a variety ofdifferent maps on the basis of the captured electrophysiologic data.

FIG. 3 illustrates a map display window 300 which an operator can use togenerate a three dimensional map of the cardiac data. The map displaywindow 300 contains menus, toolbars, a control panel and views thatallow the user to perform many functions including the loading of CTgeometries and manipulating one or two heart chamber views (e.g., Zoom,Rotate), locating channel positions upon which multiple forms ofanalysis are done, displaying a “map” with the resultant analysis datain tabular format (the results data grid 362), displaying waveforms foranalysis channels related to the resultant analysis data (e.g., the LATwindow 370), and configuring map templates (e.g., Channel positions,electrically passive areas) as discussed with regard to FIG. 2.

At any given time a three dimensional map can be displayed within apanel 310 and can be rotatable, zoomable, and otherwise manipulablethrough a variety of controls 312. Each of these controls can beselected using a conventional mouse or other input device. Maps can bedisplayed from a variety perspectives such an anterior posterior,posterior anterior, left anterior, oblique right anterior, oblique, leftlateral, right lateral, inferior, superior, using controls 314. Thefeatures that are displayed on a given map can vary and can be selectedor deselected by a user through control box 320. Using the check boxeswithin control box 320, the user can elect not to display map at all orif a map is to be displayed, the user can include or exclude the datapoints themselves (to thereby show only the interpolated data), theablation sites if any, labels, and the anatomy (meaning that the datapoints can be displayed without the underlying model being displayed),markers, and the actual channels that are being mapped. In FIG. 3, themap is a local activation time map, but the map module can generate avariety of other maps, including a voltage map (indicative of health oftissue) a cycle length map, a dominant frequency map, a map of customparameters (e.g., a correlation map, a temperature map, an impedancemap, etc.).

Also, plural map panels 310 can be displayed, such as two panels. Thispermits pre- and post-ablation maps to be displayed along side oneanother for physician review. The software can link plural maps to eachother or to underlying data in the results data grid 362.

A color coding is applied to the map which depicts variations inactivation time or any other parameter being mapped in accordance with acolor scale. A color scale 316 can assign a color to each data point inthe range of calculated values. The values used for assigning the colorrange can be, for example, the minimum and maximum values within theresults data grid 362 of the event log 360. Thus, with respect to theactivation time calculations shown in FIG. 3, the earliest activationtime is assigned red and the latest activation time blue, with thosecolors applied to the spheres at the location of the respectivemeasurements and a spectrum of colors on the color scale 316interpolated across the cardiac model between the measurement locations.In a conventional manner, an ectopic focus can be displayed in red.

The map display 300 has several panels which cooperate to provide theuser with an interactive map creation experience. Panel 310, displays athree dimensional map, while panel 320 provides the user with controlsover the manner in which the map is displayed. Panel 330 providesselection buttons so that the user can vary the type of map which is tobe created. Controls 340 impact the type and amount of data that iscaptured during the course of an EP procedure. Selection list 350enables the user to select different channels for any given map, and inthis regard, it should be noted that the map displayed in panel 310concerns a single active channel (the mapping channel). Of centralinterest, however, is an event log 360 which maintains the data usefulin constructing maps and synchronizing the LS Pro or other EP systemthat may be used with the mapping module. Synchronization of the mapmodule windows/panels with the EP system can be achieved bydouble-clicking, for example, on a row in the event log or on a datapoint on the map or on a point on the electrogram.

The event log is populated in response to the user recording data duringthe course of the EP procedure. In part, the event log is a visualdisplay of the contents of a data structure that manages the informationassociated with each channel, on an event-by-event basis. The datastructure can be organized by channel, and each channel can havemultiple records—one for each event. A given record, therefore,identifies a channel, the event number, fundamental information capturedfrom an electrode such as a voltage, temperature, or impedance, arecording time at which the event was logged, calculated values (such aslocal activation-times, dominant frequency, cycle length, etc.), thecolor accorded to a given channel on the EP system display (so that themapping module depicts electrograms for each channel in the same coloras used by the EP system), any fluoroscopic image that is associatedwith that channel at that recording time, the position on the anatomicalmodel at which the channel has been associated, and potentially otherinformation. Through the exchange of messages between the Lab System (orother EP System) and the map module, which include the contents of adata structure such as described above, the map views, ECG waveform, andevent data can be mutually synchronized and responsive to userselections with the display of any of this information to coordinate thedisplay of the other views. In other words, if the operator scrollsthrough the timeline of the ECG waveform within the LAT view 370 andselects an event of interest on a given channel, the values on the otherchannels will be brought into view in the grid 362 and the map in panel310 will depict the calculated values for the locations selected forthat moment in time. If the operator then selects a different channel asthe active channel for that same point in time, the LAT view 370 willupdate to synchronize with that selection.

The data in each event log entry can be displayed in one or moredifferent maps. Thus, the activation time is displayed in an activationmap and the cycle length data is displayed in a map of cycle lengths.The operator can move a current data point, whether it is recorded datacaptured by the EP system and sent to the map module as a message orwhether it is a perceived position of an ablation site or an anatomicalmarker. A right-click within the 3D view, for example, can provide theuser with such control through the user interface.

A variety of anatomical markers can be selected through a dialog box orother user-interface construct. These markers can be pre-defined, suchas:

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The map display 300 further includes a panel 370 that provides adedicated display of local activation time (or another parameter ofinterest), together with the relevant markers. The markers in the LATdisplay, in the results data grid, and in the map are all linked so thatany change on the EP system causes corresponding updates to the markers,and vice versa. The LAT window displays a number of the waveform pointsacross the region of interest and on either side thereof for theselected mapping channel reference channel, and ECG channel. The numberto be displayed is configurable, and all of the markers and electrogramsacross each channel (e.g., all active channels on the LS Pro) can bepresented in individual LAT displays. Controls are provided to stretchthe horizontal (time) axis, to zoom the amplitude, to scroll to earlieror later beats, and to reset to the default user configuration.

The events in the event log, and the data contained therein, are whattransform an anatomical model of the heart into a three dimensional mapof the cardiac data of a given EP procedure. The mapping module of thepresent invention generates a three dimensional cardiac map with regardto assigned positions of the available channels, and not with regard toactual position of any electrode within or upon a patient. As a result,the channels can be repositioned, if desired, or as a result of roving amapping catheter, without regard to its actual position, yet stillproduce a three dimensional cardiac map. The way in which this isachieved, in accordance with a salient aspect of the present invention,is best understood with further reference to FIGS. 1 and 3.

At block 108 of FIG. 1, an operator pilots a catheter under fluoroscopicguidance to locations within the patient's cardiac chamber underinvestigation. At intervals, a fluoroscopic image is displayed on afluoroscope which reveals the present location of a catheter relative tothe patient's anatomy. Using the operator's skill and experience, thatgeneral position can be identified within the template selected duringthe setup process (Block 104) and the location indicated on the cardiactemplate. Optionally, the physician can call out a grid position thatidentifies in two-dimensions the location of the electrode for themodule operator to note on a grid overlay of the template. In thisregard, the physician and the map-module operator can view the samescreen or two screens showing the same information so that the operatorcan more accurately record the location selected by the physician. Inany event, the location is indicated by clicking on the map. By clickingon the map, a new location is associated with the template, but no datahas yet to be captured. The operator can record the point using control342 (or control 344 described below). A message is then sent from themap module to the EP system requesting the cardiac data for the selectedpositions at that point in time be provided to the map module for thatchannel.

Conveniently, the results data grid 362 manages all of the values thatpopulate the various windows and panels of the map module, and so thecontents of this data grid can be used to construct messages for sendingto the EP system, and the grid has defined fields that are ready toreceive field-delimited data from the EP system. Field delimited data isa generally available output of most EP systems, including the LS Pro,so that the data can be exported from the EP system and imported intoother software packages.

Also optionally, a fluoroscopic overlay can be provided over the mappanel 310 with the same scale, magnification and orientation as thesegmented model to provide a manual guide as to the actual position ofthe catheter relative to the segmented model, or to provide an automateddetermination of position of the catheter relative to the segmentedmodel. The manual guide has the operator confirming each electrodelocation within the segmented model whereas the automated guide has thesoftware performing the confirmations automatically by matching thedarkened portions of the image (where the radiopaque electrodes arelocated) with positions within the segmented model. Of course, a hybridapproach can propose the positions to the operator with the operatormaking the final determination as to whether to accept the positionsinto the model. This approach can improve accuracy as compared torelying on a perceived location, and can be achieved free of sensors totrack the location and orientation of any or all electrodes. Theoperator then records the point or points using controls 342, 344. Amessage is then sent from the map module to the EP system requesting thecardiac data for the selected positions at that point in time beprovided to the map module for that channel. Thus, in this example, asingle location on the map has been selected as corresponding to aparticular fluoroscopic location, as indicated at block 110. Asindicated at block 112, the operator instructs the map module to recordthe data point associated with that channel, which is done byinteracting with control 342. The EP data is transferred from the LS Proor other EP system to the map module, which in turn performscalculations such as the activation time, the cycle length, the dominantfrequency, etc., as indicated at block 114. Cycle length can becalculated as described in co-pending U.S. patent application Ser. No.11/120,633, entitled “High Density Atrial Fibrillation Cycle Length(AFCL) Detection And Mapping System,” filed on May 2, 2005, which ishereby incorporated by reference in its entirety. The data received fromthe EP system, and each of the calculations that is to be performed, arepopulated within the event log 360. It should be noted, that to minimizeburdens on the processor executing the map module, only thosecalculations that are necessary for the selected map need to beperformed at any given time, but they preferentially can be done inadvance so that the user can rapidly switch between maps of ActivationTime, Voltage and DF. Each map is created by applying a respective,suitable signal processing algorithm (as known in the art) to the dataassociated with the selected set of channels (data points on the map).Thus, if activation time is the selected map type (as illustrated inFIG. 3), then Fourier analysis need not be done on the data because nofrequency calculations are required. Once the calculations areperformed, which can occur within a matter of seconds or less, theresult of the calculations can be displayed in the event log asindicated at block 116 and the local activation window 370 can bepopulated with the waveforms associated with the channel underinvestigation, as indicated at block 118. With further reference to thelocal activation time (“LAT”) window 370, once data has been capturedover a region of interest that window can be populated with thewaveforms over that interval, as well as indicators which correspond toa reference channel marker and the mapping channel marker, thedifference defining the activation time at the current location of themapping catheter.

As noted, the event log is updated with the calculations that have beenperformed as well as the data received from the EP system, as indicatedat block 120. In addition, the activation time that has been calculatedis placed onto the map. Preferably, the data points that are added tothe map comprise color indicators, and more preferably compressed colorspheres, which at least partially project from the surface of the map inorder to provide a visual indication as to where the data was captured,as opposed to data that has been interpolated. Once at least three datapoints have been so captured by performing blocks 112 through 120, thesurface of the cardiac model can be interpolated and a three-dimensionalcontinuous color changing map can be rendered, as indicated at block122.

The size of the measurement spheres that is depicted on the segmentedmodel is user configurable and can be changed to emphasize to the userthe difference between measurement positions and interpolated data.

Interpolation of the data is performed with regard to electricallyactive areas of the model. Interpolation is invoked whenever a datapoint is recorded once there are three or more data points in theresults data grid. Interpolation is also invoked whenever a data pointreference position or roving position is adjusted in the LAT window 370,or in a similar waveform window showing a different parameter. In bothof these cases the three main types of analysis data are interpolated,namely, LAT, voltage and dominant frequency. Custom and cycle lengthanalyses can be interpolated if there is data in the associated columnof the current results data grid 362.

If a template is used, one or more neutral areas can be identified astissue not subject to data interpolation. For example, the segmentedmodel can include a portion of the arch of the aorta which can beisolated from the electrically active area by a boundary zone. Theboundary zone can be part of the template's definition, and can bere-defined by the user, as desired, by paint or dragging operationsusing a mouse or other input device. In a similar way, a chamber can beexcluded from interpolation by defining a boundary zone so as to excludeit from other tissue in the cardiac model. Any boundary zone so definedcan be saved, regardless of whether the model was a template from alibrary or the patient's own cardiac CT image.

As noted above, a user may prefer to view the data points without theanatomical model overlay. This may be advantageous in situations inwhich the clinician wishes to see precisely where data has beencollected, and not have that information obscured by the interpolation.The interpolation process results in a continuously changing colorpattern across the surface of the anatomical model which providesinsight to the clinician as to the location of the earliest activationtime, locations of necrosed or diseased tissue, indications of anaberrant cycle length, and the like. However, there are situations inwhich it is preferable to remove the anatomy from the display, if onlyto observe where data has been collected already. To further assist theclinician in identifying those locations where it may be desirable tocollect additional information, and in accordance with a further aspectof the invention, the activation map (or any other map being created)can be rendered in a semi transparent mode. This allows the user to seethrough to the inside of the heart and preferably increases in opacityin those regions in which there has been a high density of data pointscollected and to remain transparent in regions where there are few or nodata points. In this way, the user is provided with a qualitativeperspective on how reliable or accurate the interpolation is in anygiven area. This is illustrated in FIG. 5 in which the panel 510 issubstantially the same as panel 310, except the semi-transparent modehas been enabled. As a corollary, then, it should be understood that theopacity at locations that include mapped EP data is greater than theopacity at locations that do not include any or as much EP data mapping.

Referring again to FIG. 1, the calculations performed by the map moduleinclude, among other things, the application of raw data collected fromthe electrodes (which correspond to each channel under investigation) tothe waveforms in order to arrive at various calculations such asactivation time. In connection with the use of these algorithms, anexact location of the marker on the reference channel is identified bythe algorithm for use in the calculations. This refinement in the markerlocation for the reference channel, as well as the calculations thatwere made on the data by the map module, is provided to the EP system inan electronic message, as indicated at block 124. As a result, the EPsystem is provided with the calculations performed by the map module asdisplayed in the event log 360, in the local activation time window 370and in the map pane 310. As can be seen in FIG. 4, one or moreactivation time callouts are illustrated in conjunction with respectiveactive channel to inform the clinician of the activation time of theactive (mapping) channel as compared to the other active channels. Thus,in FIG. 4, the mapping channel is HRA and has activation time of 5milliseconds as compared to the other channels under investigation whichhave activation times of 33-73 milliseconds, all relative to thereference channel marker. As will be understood by those of ordinaryskill in the art, this indicates that the present location of the rovingcatheter HRA is comparatively close to the earliest activation time thathas been identified, so far, and therefore indicative of the situs ofthe cardiac arrhythmia.

The clinician may wish to continue moving the mapping catheter about thecardiac chamber under investigation in order to find additional orbetter or different data about the heart's response to its naturalcycle, or in response to a pacing electrode (not shown). Thus, at block126 a test is made to determine whether to repeat the mapping steps foran additional channel, which for purposes of this disclosure includesrepeating the mapping steps for the same channel. In a manual mode ofoperation, the clinician can continue the process by piloting thecatheter to a new location within the cardiac chamber, again underfluoroscopic guidance as indicated in block 108) and then repeat steps110-124 in order to capture additional electrophysiologic data, performdesired calculations on that data such as calculation of activationtime, and to update the map in panel 310 and the event log in panel 360and the local activation time window in panel 370 and to annotate theelectrogram signals in the EP system through messages passed between themap module and the EP system.

The foregoing steps can easily be repeated in an automated manner when amultipole catheter is being used. Referring briefly to FIG. 6, amulti-channel catheter has several active channels on the cardiactemplate and electrophysiologic data for each of those channels can becaptured by the foregoing steps and a signal recording time by selectingthe “record all” control 644 shown in the map display 600. Therecord-all control is similar to the record-point control except that itcauses the process to be iteratively performed until each of the activechannels has its data captured, calculations performed, and updates tothe respective windows, maps, event logs and electrograms, as previouslydescribed. It should be understood, however, that while the record-allcontrol enables data to be acquired from the active channels all at thesame time, the calculations and updating of display follow one anotherin time. Nevertheless, all of the foregoing steps can be performed in amatter of seconds or less.

Once the clinician is satisfied that sufficient data has been gatheredto construct a map—including a sequentially obtained map as describedwith regard to FIG. 3 or a multi-channel map as described in connectionwith FIG. 6 or a composite map which is a hybrid of both single pointand multi channel acquisitions—then the clinician can considerperforming a treatment on the heart to overcome its ailment. Forexample, the treatment can be an operation in order to eliminate orreduce an arrhythmia. The semi-transparent mode can be actuated tosatisfy the clinician that he has gathered sufficient data within theregion at which the focus appears to be located.

It will be appreciated that a composite map includes single-beatmultichannel data and single channel data from different cardiac beats.A composite map can result from the use of a multi-electrode catheterfor rapid data acquisition in a single beat followed by a point-by-pointmapping to fill-in areas of interest.

Throughout the progress of the EP procedure, the map module of thepresent invention can provide further functionality to assist theclinician in mapping and treating heart problems. For example, control346 and 646 illustrated in FIGS. 3 and 6, respectively, can be used tocapture an image at the particular location of the mapping catheter atthe time a particular event is taking place. For instance, the imagebeing captured can be a fluoroscopic image. The fluoroscopic image isnot only captured, but it is stored within the data structure inassociation with the event number. As a result, each mapped channel canhave a fluoroscopic image associated with its position at the time ofthe event, its electrogram data, as well as the recording time.Likewise, each mapped position on the map itself is associated throughthe event log 360 with any fluoroscopic image that was captured when thedata was captured at that electrode position, such that a user can clickon the map and cause the software to recall the associated fluoroscopicimage, or click on the event in the event log. Consequently, a physiciancan retrieve the fluoroscopic image and use it to guide back to alocation of interest, or can use this feature during a review mode tomore generally coordinate past locations, as identified by the capturedfluoroscopic image, with specific waveform electrogram sets across thevarious channels of investigation and with a 3D image of the electrogramdata.

It should be appreciated that the control 346, 646 can associate afluoroscopic image with the results data grid for coordinated retrievalin relation to the data recorded at the time of the event, and also canassociate other data that is captured in association with an event. Asnon-limiting examples, EP systems can also include ultrasound datacapture and other positioning systems that determine the location of anelectrode or the catheter, and that information can be stored inassociation with the electrograms and calculated measurements.

Thus, at block 128, a test is made to determine whether the clinicianwishes to capture an image, and if he does then the fluoroscopic imageis stored and associated with the event at block 130. Thereafter, testsare made first at block 132 and then at block 134 to ascertain whetherthere has been manipulation of any of the data at either the map moduleor the EP system, respectively.

In the event that there has been manipulation of data at the map module,a first test is made at block 136 to determine whether it is amanipulation of only the map itself. The map can be manipulated, forexample, by the clinician relocating a channel along the surface of themodel. In that case, the data displayed on the map and within the eventlog 360 is updated so as to re-interpolate and render once again a mapin accordance with those changes. If the data manipulation at the mapmodule concerns a change in location of the mapping channel marker or ofthe reference channel marker, then a message is sent to the EP system inorder to synchronize it with such changes made at the map module. Thepurpose of the synchronization is to ensure that the map module and theEP system are operating under the same underlying parameters andsettings. Re-interpolation is performed at block 138 and any messagesthat are sent to the EP system are done, as indicated at block 140.Continuing, an event that data manipulation has occurred at the EPsystem, such as the clinician determining that a new region of interestis appropriate, then a message is communicated to the map module, asindicated at block 142, to provide it with the changed parameters. Anymessage received from the EP system at the map module is processed byupdating the contents of the event log. The event log, as noted above,serves as a central repository as the parameters with values andcalculations that instruct the creation of the three-dimensional maps inpanel 310.

Referring now to FIG. 7, a review mode is provided in which theclinician or operator can inspect any of the entries within the eventlog 360. At step 710 a test is made to determine whether data from theevent log has been selected. At any time, because the interface is eventdriven, the user can select a variety of actions including going into asetup mode, rotating or zooming the map image, changing the perspectiveview of the image or changing the type of map to be displayed and so allsuch other actions can be handled at block 720. In the event that theuser has interacted with one of the entries in the event log, then oneor more windows are updated with the selected channel data, as indicatedat block 730. In FIG. 3, for example, event No. 1 has been highlightedand the local activation time window 370 shows the selected channel atthat point in the electrophysiologic procedure. Upon selecting entry No.1, a message is conveyed to the EP system with the event number, therecording time and other information such as the dominant frequency (ifcalculated), as indicated at block 740. The EP system responds to thatmessage as though it was a command received through its user interfaceand causes the electrograms to be recalled for that recording time.Consequently, the data displayed in the map module and review mode isagain synchronized with the data in the EP system, as indicated at block750.

By synchronizing the EP system with the map module, a full set of allchannels on the EP system can be displayed that correspond to theselected event. Thus, comparing the electrograms of FIG. 4 to the localactivation time window 370 of FIG. 3, it can be appreciated that the LATwindow 370 shows only a portion of the waveform within the region ofinterest for the mapping channel, its reference channel and one of theECG channels, whereas the multi-channel display at the EP system shownin FIG. 4 provides the mapping channel in relation to all the otherchannels available in the procedure. The EP system is able to navigatealong the time line of the electrograms and locate the selected eventusing the information that is provided in the message from the mapmodule t the EP system. That full set of information is displayed on theEP system as indicated at block 760.

Referring now to FIGS. 8A and 8B, panels 310A and 310B are dual views ofthe same cardiac model showing different points in time of an EPprocedure, namely, pre-ablation and post-ablation views of the heart,respectively. These views can be displayed alongside each other, ifdesired. These figures also show an orifice that the operator can createusing the anatomy editor feature, which can be made available, forexample, using a tab or other interactive control provided through thegraphical user interface. The orifice is created by painting segments ofthe anatomical surface. A check box or the like enables the user toselect this functionality. Thereafter, a click and drag operation canselect a region. The selected region can turn gray, for example. Theuser can then command the map module to turn the selected region into anorifice, which then appears transparent to permit the operator to seewithin the chamber. This process is similar to the steps taken to makeareas electrically passive (boundaries, scars).

In use, therefore, the operator can position ECG leads within one ormore cardiac chambers and set the region-of-interest markers to identifya particular beat on the time-based ECG waveform in the LAT window 370.When data for a point on a given channel or from multiple channels is tobe captured, a record control is selected from the map module, and thatcauses the captured data to be transferred to the EP system asfield-delimited data or as a data object by the map module. Likewise, ifthe operator selects a different channel as the active channel or as thereference, or changes the region-of-interest, etc., messages communicatebetween the EP system and the map module to ensure that the variousviews into the underlying data remain synchronized. In part, thisenables the operator to navigate the ECG waveform's time line to find anevent of interest, and then be able any data recorded on any of therecorded channels at that particular point in time. As such, theinvention provides a tool useful for both diagnostic and therapeuticactivities.

While exemplary drawings and specific embodiments of the presentinvention have been described and illustrated, it is to be understoodthat the scope of the present invention is not to be limited to theparticular embodiments discussed. Thus, the embodiments shall beregarded as illustrative rather than restrictive, and it should beunderstood that variations may be made in those embodiments by workersskilled in the art without departing from the scope of the presentinvention as set forth in the claims that follow, and equivalentsthereof. In addition, the features of the different points set forthbelow may be combined various ways in further accordance with thepresent invention.

1. A computer-assisted method for guiding an operator in definingelectrode positions upon a display of a segmented heart model, in orderto construct a more accurate map than achievable without such guidance,the segmented heart model being included in a map panel on a displayscreen, comprising the steps of: advancing a catheter into a beatingheart, the catheter having a proximal end and a distal end that supportsone or more electrodes; obtaining an image during a beat of the heart,the image including one or more darkened portions corresponding tolocations of the one or more electrodes; presenting the image in thesame map panel that includes the display of the segmented heart model;confirming a current location of the one or more electrodes at theactual position of the catheter relative to the segmented heart model;capturing EP data that represents electrophysiological signals of thebeating heart at the current location for each of the one or moreelectrodes; applying a signal processing algorithm to the captured EPdata in view of the confirmed current location of the one or moreelectrodes to result in a calculation; and mapping the calculation atthe confirmed location of the one or more electrodes.
 2. The method ofclaim 1, wherein the presenting step presents a fluoroscopic image asthe image.
 3. The method of claim 1, wherein the image comprises anoverlay over the map panel that includes the display of the segmentedheart model.
 4. The method of claim 1, wherein the image is presentedwith the same scale, magnification and orientation as the segmentedmodel relative to the patient.
 5. The method of claim 1, wherein the oneor more electrodes are radiopaque electrodes.
 6. The method of claim 1,wherein the catheter is free of sensors to track the location andorientation of any of the one or more electrodes.
 7. The method of claim1, wherein the confirming step comprises the operator confirming eachelectrode location within the segmented model.
 8. The method of claim 1,further comprising the step of automatically determining a position ofthe one or more electrodes within the segmented model by matching eachdarkened portion of the image as a corresponding position of eachelectrode.
 9. The method of claim 1, wherein the automatic determiningstep is performed by software.
 10. The method of claim 1, furthercomprising the steps of: automatically determining a position of the oneor more electrodes within the segmented model by matching each darkenedportion of the image as a corresponding position of each electrode;proposing the automatically determined positions to an operator of thecomputer-implemented method; and receiving from the operator anacceptance of the proposed the automatically determined positions,wherein the automatically determined positions are included into thesegmented heart model as a function of the operator's acceptance. 11.The method of claim 1, wherein the signal processing algorithm executesin a first machine and wherein the mapping step executes in a secondmachine, the method including the further steps of: transferring over anetwork connection the confirmed location of the one or more electrodesfrom the second machine to the signal processing algorithm executing inthe first machine; and returning the calculation at the first machine tothe second machine.
 12. The method of claim 1, further comprising afterthe mapping step the steps of repositioning the catheter once advancedwithin the beating heart and repeating each of the remaining steps. 13.The method of claim 12, wherein the mapping step further comprises:performing interpolation calculations for regions of the segmented heartmodel between confirmed electrode locations; and applying a color scaleusing the interpolation calculations.
 14. A computer-implemented systemfor guiding an operator in defining electrode positions upon a displayof a segmented heart model, useful in the construction of a moreaccurate map than achievable without such guidance, the segmented heartmodel being included in a map panel on a display screen, comprising:means for obtaining an image during a beat of a heart, the imageincluding one or more darkened portions corresponding to locations ofone or more indwelling electrodes supported on a catheter; firstsoftware code executing so as to present the image in the same map panelthat includes the display of the segmented heart model; second softwarecode executing so as to confirm a current location of the one or moreelectrodes at the actual position of the catheter relative to thesegmented model; means for capturing EP data that representselectrophysiological signals of the beating heart at the currentlocation for each of the one or more electrodes; third software codeexecuting so as to apply a signal processing algorithm to the capturedEP data in view of the confirmed current location of the one or moreelectrodes to result in a calculation; and fourth software codeexecuting so as to map the calculation at the confirmed location of theone or more electrodes.